Color coding of optical fibers is well known and widely used. The standard colors for optical fibers follow the traditional standard for electrical wire, namely:
Fiber NumberColor1Blue2Orange3Green4Brown5Slate6White7Red8Black9Yellow10Violet11Rose12Aquawhere white and black are considered colors for the purpose of this description. As is evident, this group of colors allows effective coding for twelve optical fibers in an optical fiber cable. However, high fiber count cables in commercial use often have more than twelve optical fibers, often many more.
To overcome this limitation, use of multiple colors has been proposed. One such proposal is described in U.S. Pat. No. 6,317,553. This patent describes, inter alia, the use of a continuous thin color stripe extending along the length of the optical fiber. With a background color and the stripe color, and the color options in Table 1, it is possible to have 66 color combinations.
In some applications, particularly field applications, the working conditions are such that it may be difficult to discriminate these color combinations, especially to identify the color of the thin stripe.